LPFA FracRak Format
Bananalogue is proud to present our first module in collaboration with Rob Keeble of Analog Metropolis!
The Bananalogue LPFA is a clone of the Arp 4075 4-pole 24dB low pass filter in the Arp Odyssey Mark III, later Arp 2600 models, as well as the Odyssey and Quadra. The LPFA contains the original Arp module circuit as well as the additional circuitry of CV and signal summing which is held on the main Arp PCB's, providing a self contained module for use within the modular system, rather than a replacement module for Arp synthesizers.
This filter has a clean, low distortion output that will oscillate at higher resonance settings. The control inputs are accurately calibrated to 1V/octave, and there are two CV inputs which have front panel attenuators. There is also an un-attenuated CV in for direct connection to a keyboard CV.
The filter frequency has two front panel controls for coarse and fine adjustment, there is also an on-board trimmer to set the initial cut-off frequency. The filter has a Q control to adjust the resonance of the filter. Higher settings of the Q control will take the filter into sine wave oscillation.
This module is a voltage controlled 4-pole 24dB low pass filter with resonance. The module has three attenuating inputs, so if no filtering is applied it may also be used as a simple audio mixer.
Rob Keeble has also prepared a detailed PDF manual and construction notes for this module available from the Analog Metropolis website here:
AM4075
A Frequency control
B Resonance control
C Fine Frequency control
D KBD CV input
E CV 2 attenuator
F CV 2 input
G CV 1 attenuator
H CV 1 input
I Input 1 attenuator
J Input 1
K Input 2 attenuator
L Input 2
M Input 3 attenuator
N Input 3
O Output